Heat exchanger



F IG. 2.

INVENTORS L H GREATHOUSE SMITH ROBINSON C H. HAYDEL K q ATTORNEY B AH.M.

- April 14, 1959 L. H. GREATHOUSE ETAL HEAT EXCHANGER' OfiginaLFiledAug. 26, 1952 FIG. 1.

United States Patent HEAT EXCHANGER Lucien H. Greathouse, Burns AshbySmith, Helen M. Robinson, and Chester H. Hayde], New Orleans, La.

Original application August 26, 1952, Serial No. 306,517,

now Patent No. 2,744,014, dated May 1, 1956. D1- vided and thisapplication August 2, 1955, Serial No.

1 Claim. (Cl. 257-1) (Granted under Title 35, U. S. Code (1952), see.266) A non-exclusive, irrevocable, royalty-free license in the inventionherein described, throughout the world for all purposes of the UnitedStates Government, with the power to grant sublicenses for suchpurposes, is hereby granted to the Government of the United States ofAmerica.

This invention relates to a heat exchanger of the general type in whicha tank is provided with inlet and outlet openings comunicating with thetank for passage of the heating fluid, and with at least one heatexchanger tube in the tank having inlet and outlet openings comunicatingwith the tube arranged for flow of the liquid to be heated through thetube.

According to the invention means is provided for clean ing adheringdeposits from the inside surface of the tube. Such means comprises, ingeneral, a scraper in the form of a flexible, circular split bandbearing against the inner surface of the tube and being open so thatdeposits may be removed from the inner surface of the tube by longitudinal movement of the scraper while allowing a substantialnon-turbulent flow of the liquid being heated past the band. The scraperis attached to a handle which extends through an opening in the tank inline with the tube. The ends of the band are slidingly joined,permitting it to undergo small adjustment to conform to the size of thetube and still scrape it efiectively.

The heat exchanger of the present invention is particularly useful inthe heating of fine starch fruit water such as that obtained in theproduction of sweet potato starch. The heat exchanger may be operatedcontinuously and the heat exchanger tube efliciently kept clear ofdeposits, thus keeping constant the heat exchange rate. Deposits tend toinsulate the tube so that the build up of deposits detrimentally variesthe heat exchange characteristics of the exchanger. In case of heatingfine starch fruit water, it is desirable to keep the water in anon-turbulent state.

For a detail description of the invention reference is made to theaccompanying drawing in which Fig. 1 is a vertical section of theexchanger on line 1--1 of Fig. 2;

Fig. 2 is a horizontal section on line 2-2 of Fig. 1;

Fig. 3 is an elevation of the scraper with parts broken away; and

Fig. 4 is a section on line 4-4 of Fig. 3.

Tank of the exchanger is provided with inlet and outlet openings 11 and12 for passage of the heating fluid. Headers 13 and 14 and a number ofvertical heat exchanger tubes of usual construction are provided. Theliquid to be heated enters through inlet 15 flows upward through thetubes and discharges through outlet 16. The several tubes and associatedscrapers are similar and only one tube and its associated scraper 21will be described in detail.

The scraper is provided with a flexible circular split band 22,preferably of spring steel. The ends of the 2,882,022 Patented Apr. 14,1959 band overlap and are slidingly joined, outwardly projecting pins 23and 24 affixed to the innermost end operating in elongated slots 25 and26 in the outermost end to hold the ends in alignment. The band bearsagainst the inner surface of the tube, the lower edge of the band beingbeveled inwardly to guide its entrance into the tube. Handle 30, in formof a rod, extends upwardly through opening 31 in the tank, the lower endof the handle being attached to the band. The handle is of such lengthas to provide for movement of the scraper throughout the length of theheat exchanger tube.

The handle is attached to the scraper in a manner to allow free flexingof the band, thus to permit the band to bear against the inner surfaceof the tube and adjust to slight irregularities, and also to permit asubstantial nonturbulent flow of the liquid being heated past the band.To this end cross straps 32 and 33 are attached to their outer ends tothe upper edge of the band at diametrically opposed points remote fromthe split ends. The inner ends of the straps overlap and are providedwith elongated slots through which the handle is loosely passed. Straps35 and 36 of spring steel are attached at their upper ends to the band,the lower ends being afiixed to the lowermost end of the handle as bywelds 37 and 38.

Sludge which collects in the bottom of the heat exchanger may bedischarged through sludge valve 40.

This application is a division of application Serial No. 306,517 filedAugust 26, 1952, now Patent No. 2,744,014 issued May 1, 1956.

Having thus described our invention, we claim:

A heat exchanger comprising a tank, at least one heat exchanger tubewithin said tank, inlet and outlet openings communicating with the tank,inlet and outlet openings communicating with the tube and arranged forfiow of liquid to be heated, an opening in the tank in line with thetube, a handle extending through the opening, and a scraper attached tothe handle within the tube for removal of deposits from the interiorsurface of the tube, said scraper comprising a flexible, circular splitband, the ends of the band being slidingly joined, permitting the bandto undergo small adjustment to conform to the size of the tube and stillscrape it effectively, the band bearing against the inner surface of thetube and being open so that the deposits may be removed from the innersurface of the tube by longitudinal movement of the scraper whileallowing a substantial non-turbulent flow of the liquid being heatedpast the band.

References Cited in the file of this patent UNITED STATES PATENTS 13,628Weissenborn Oct. 2, 1855 273,777 Strong Mar. 13, 1883 321,541 ShepardJuly 7, 1885 440,410 Nelson Nov. 11, 1890 443,186 Alberger Dec. 23, 1890810,441 Stump Jan. 23, 1906 1,116,953 Testrup Nov. 10, 1914 1,581,545Prache Apr. 20, 1926 1,621,289 Sternberg Mar. 15, 1927 1,668,577 VecchioMay 8, 1928 1,686,715 Smith Oct. 9, 1928 1,770,208 Kemnal July 8, 19302,233,066 Watson Feb. 25, 1941 2,733,767 Sappington Feb. 7, 1956 OTHERREFERENCES Babbit: Sewerage and Sewage Treatment," 6th ed. (1947),published by Wiley & Sons (N.Y.), p. 397 (first full paragraph).

